FINITE ELEMENT ANALYSIS OF THERMOGRAPHY TECHNIQUE FOR DEFECT IDENTIFICATION IN CONCRETE SLAB

Abstract

Non-destructive evaluation is an area of focussed research around the world. Through non-destructive evaluation it is aimed at evaluating the integrity of concrete and identify the location of defects like voids and honeycombs. While most of these methods rely on wave propagation, the infrared thermography technique uses heat conduction principles to identify defects at shallow depth. The infrared thermography technique is a non-contact non-destructive testing technique which makes it possible to evaluate the test medium independent of its surface characteristics. Also, the ability of the infrared thermography camera to capture and assess a surface area at every time instant makes it an interesting technique to pursue research on. In the present work, it is proposed to examine the possibility of defect identification using the infrared thermography technique by employing the finite element analysis. For this study, two case studies have been carried out. For the analysis a standard commercial FEM package has been used and the heat transfer analysis is carried out using ten node tetrahedron elements by incorporating the thermal properties. Heat is applied from one surface and the evaluation is carried out from the same surface. Encouraging results have been obtained on the application of the thermography method. In the present study, it has been observed that the thermography method could be effectively applied for large defect identification up to a depth of 90mm from the investigating surface.